Mountain biking, a branch of the bicycle industry that has become increasingly popular, has evolved to provide off-road equipment for transportation, racing, and recreation. A derailleur assembly (i.e., the mechanism used to switch gears) of a bike often disables when an object, such as a stick or rock, impacts the derailleur or becomes wedged between the derailleur and the frame or the wheel of the bicycle. Damage to the frame, the derailleur, or the derailleur hanger almost always results. As a result of the damage to the derailleur assembly, the bike becomes disabled, leaving the rider stranded. With the limitation on weight and space, it is impractical for a rider to carry sufficient spare parts or tools to repair the damaged derailleur assembly at the site. The repairs, if possible, will be costly and time consuming.
Two traditional designs are used to attempt to protect the bicycle frame from becoming damaged. These designs are incorporated between the derailleur and the bicycle frame. The designs are structural weak links so as to deform or break rather than allowing the bicycle frame or derailleur to be damaged. These designs include a deformable derailleur hanger and a mounting bolt of softer material than that of the bicycle frame and/or derailleur. A deformable derailleur hanger protects the frame, but does not extend to preserving the derailleur. A softer mounting bolt has a tendency to flex excessively under reasonable loading. By protecting the bicycle frame or derailleur, both of these designs render the bicycle disabled and make field repair impracticable.
Another field serviceable derailleur device similar to the present invention requires exact alignment between three internal tool opening surfaces having the same cross-sectional area and shape. This field serviceable derailleur device requires careful production and installation.
The problem with requiring exact alignment with three internal tool opening surfaces so that the designed shear point is not stressed during installation is that there are numerous manufacturing difficulties. These difficulties are eliminated in the current invention by using a separate set of actuating features for two of the parts that do not interfere with the actuation of the third and by reducing the number of internal connections required. Additionally, this revision eliminates the need to precisely set the depth of the tool during installation and removal of the device. Finally, the previous device was highly sensitive to the torque with which the device was installed, leading to variability in the force required to fracture the pin, thereby making the device prone to premature pin fracture. The current invention employs a depth stop to control the torque loads applied to the device during installation.
The present invention is generally directed to bicycle derailleurs, specifically a device to protect the derailleur and derailleur hanger of a bicycle from being damaged and allowing for field serviceability.
In general, according to one aspect, the invention apparatus concerns a field serviceable device that reduces the likelihood of damaging a pivoting means, such as a bicycle derailleur, and stationary means, such as a bicycle derailleur hanger. The device comprises a head, a barrel, a flange, and a pin. The barrel comprises a barrel-head connector at a first end and a barrel-flange connector at a second end. The head comprises a head-barrel connector whereby the head and barrel are connected by mating the head-barrel connector of the head and the barrel-head connector of the barrel. The flange comprises a flange-barrel connector, whereby the head and flange are connected by mating the head-flange connector of the head and the flange-head connector of the flange. The pin comprises a pin-barrel connector on a first end, a pin mounting connector on a second end, and a pin fracture notch between the first and second end of the pin. The pin and head are connected by mating the pin-barrel connector of the pin and the barrel-pin connector of the barrel. The pin further comprises a pin-tool opening extending through the pin, whereby a tool is inserted into the pin. The barrel further comprises a barrel-tool opening extending through the barrel. The head further comprises a head-tool opening extending through the head. Both the barrel-tool and head-tool openings are of sufficient dimension so that the pin-tool is not interfered with when rotating the pin.
The above and other features of the invention, including various novel details of construction and combinations of parts, and other advantages, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular method and device embodying the invention are shown by way of illustration and not as a limitation of the invention. The principals and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.